Male and female pelvic bones do have different shapes- female ones are a bit rounder/wider in comparison for one. They tilt at different angles, the female hip protruding while the male is tilted down towards the spine (this dimorphism is commonly exaggerated via high heels). The public arch is different angles, and the part at the bottom where the two halves of the pelvis meet are much thicker in anatomical males. The sacrum is another big difference- its longer, straighter and narrower in men, short and curvy in women...
It looks like you probably used a female skeleton model- but hey, gender doesn't equal behavior- and besides, who's to say skeletons can't be transgender!

For what it's worth, I once witnessed a pair of radiologists debating over my Xray whether I was male or female. Eventually, they decided that it might be the right Xray as it was *probably* male, but they both admitted the other had good points for their arguments.

I've never been particularly medically inclined so all I can say is the descriptions you gave of the differences sound familiar. But they're not necessarily quite so universal.